Continuous range finder



(HR 2 a 406 9 999 Sept. 3, 1946. F. w. DURGIN CONTINUOUS RANGE FINDER Filed April 23, 1943 I NVENTOR' 3m M @myim Patented Sept. 3, 1946 OUGE UH CONTINUOUS RANGE FINDER Franklin W. Durgin, Washington, D. 0.

Application April 23, 1943, Serial No. 484,279

4 Claims.

This invention relates to improvements in continuous range finders and more specifically to a gun-coupled range finder particularly well adapted for anti-aircraft use.

The primary object of the invention is to provide a gun-coupled range finder which will automatically maintain the range finder at the proper angle to the gun when the gun is p p ly rotated and the range finder is properly focused on a moving target, such as an airplane.

Other objects and advantages of the invention will become apparent during the course of the following detailed description, taken in connection with the accompanying drawing, forming a part of this specification, and in which drawing,

Figure 1 is a diagrammatic side view of the gun-coupled range finder focused on an airplane in flight.

Figure 2 is a diagrammatic plan view of t e gun-coupled range finder.

Figure 3 is a diagrammatic view of an electrical circuit preferably forming a part of the invention.

In the drawing, which for the purpose of illustration shows only a preferred form of the invention, and wherein similar reference characters denote corresponding parts throughout the several views, the letter A generally designates the gun, to which is coupled the range finder B, focused on a moving target, such as the airplane C.

Any suitable range finder B, such as shown in U. S. Patent #279,273 to Patterson or #1,968,002 to Nowicki et al., may be employed. There is disposed, in alignment with the axis IU of elevation of the gun A, the lateral sight member ll of the range finder B having a conventional rotatable light deflector l2, constituting the movable component of the range finder. A semi-transparent mirror l3 disposed at an angle of 45 within the longitudinal sight member M at the intersection of the lateral sight member |l constitutes the fixed component of the range finder.

Any suitable motion transmitting means, such as a belt I5, is provided between the axis of rotation of the range finder and the drive shaft of a speedometer I8 whose speed indicating shaft is connected, as by a belt H, to the shaft of a suitable rheostat [8.

Any suitable motion transmitting means, such as a belt I9, is provided between the axis of rotation of the range finder B and the shaft of a suitable rheostat 20.

iii

The rotatable light deflector I2 is directly connected to the shaft of a suitable rheostat 2|.

Attached to the gun A is a solenoid 22, in series circuit with the rheostats I8, 20 and 2|, the armature 23 of the solenoid being fastened to the longitudinal sight member I4. A suitable source of current 24 is provided in the circuit, as shown in Figure 3.

The rheostats I8, 20, and 2| have resistances which are so related to the factors of aircraft speed, angular elevation, and aircraft distance, that the current in the circuit is varied in response to changes in the speed, angular elevation, and distance of an approaching aircraft whereby the solenoid will dispose the sight member M in proper angular relation to the gun A, which is angularly rotated, as by the gunner, at a rate just sufiicient to retain the images of the approaching aircraft in the range finder B.

As the speed indicating shaft of the speedometer l6 turns responsive to apparent or actual increase in speed of the aircraft, the shaft of the rheostat I8 is automatically turned so as to increase the current flow through the solenoid 22, whereby the angularity between the gun and sight member I4 is increased.

As the sight member l4 turns toward the vertical, the shaft of the rheostat 20 is gradually turned to reduce the current flow so as to compensate for any advancement of the rheostat I8 that is due to apparent but not actual increase in speed of the approaching aircraft, it being un derstood that the sight member I4 is accelerated as it approaches the vertical when the speed of the aircraft is constant.

As the light deflector I2 is turned or otherwise controlled by the gunner to retain the dual images of the approaching aircraft in proper alignment in the range finder B, the shaft of the rheostat 2| is automatically turned to increase the current flow through the solenoid, whereby the angularity between the gun A and the sight member I4 is increased.

Thus, the relationship of the sight member M to the gun A depends on the speed, angle of elevation, and distance of theapproaching aircraft C relative to the location of the gun A.

Various changes may be made in the form of invention herein shown and described without departing from the spirit of the invention or the scope of the following claims.

I claim:

1. The combination with a gun rotatable about a given axis, of a range finder mounted for rotation about the axis of rotation of the gun, said HUJUHI range finder provided with a movable distanceindicating element, a single power actuated means for controlling the angular relationship of the gun and range finder substantially in accordance with the amount of power actuating said control means, a source of energy for actuating said control means, a speedometer driven by rotation of the range finder, and plural jointly acting means for varying the amount of energy delivered to said control means including means controlled by said speedometer, means controlled by said movable element, and means responsive to changes in the angular position of the range finder.

2. The combination with a gun rotatable about a given axis, of a range finder mounted for romotive device, a speedgmeter driven by rotation 25 of the range finder, Miami-n51 "jointly acting means for regulating thef iow of current from said source to said electro-motive device com- .prising means controlled by said speedometer,

means controlled by said movable element, and 30 means responsive to changes in the angular position of said range finder.

3. The combination with a gun rotatable about 5 ship of the range finder to the gun substantially in accordance with the instantaneous value of the power actuating said control means, a source of energy actuating said control means, and plural jointly acting means varying the amount of en- 10 ergy delivered to said control means including means responsive to changes in the target-distance adjustment of the range finder.

4. The combination with a gun rotatable about a given axis, of a range finder rotatable about an 15 axis extending in the direction of the said axis of rotation of the gun, said range finder prop'dedntMigqfil klfilgfiflfifilg l ding elem ent a solenoid, a source of current energizing the solenoid, said solenoid controlling the angular relationship of the range finder to the gun substantially in accordance with the amount of energy supplied to the solenoid, a speedometer, means driving the speedometer at a rate depending on the rate of rotation of the range finder, and a plurality of serially connected impedance; for regulating the flow of current from said source to said solenoid and including a rheostat controlled by said speedometer, a rheo stat controlled by movement of said distance-finding element, and a rheostat responsive to changes in the angular position of the'range finder.

FRANKLIN W. DURGIN. 

